The present invention relates to an apparatus for automatically retrieving from a supply and inserting various types and sizes of electronic components having extending lead wires into predetermined apertures in a through-hole printed circuit board. Specifically the apparatus of the present invention includes a retrieval and insertion device with adjustable pairs of fingers with force and displacement sensors to carefully monitor and control the force exerted on and the displacement of components having different shapes during retrieval and insertion of these components into the proper location on a printed circuit board.
Automatic electronic component insertion apparatus for printed circuit boards are well known. Some insertion apparatus manipulate components based solely on a predetermined path such that upon occasional and slight deviation from that path, an insertion may be attempted without proper alignment of the component lead with the printed circuit board through-hole. In this situation either the component or the printed circuit board could be damaged. These apparatus function largely in an assembly line mode in which large numbers of similarly shaped components are sequentially positioned on a printed circuit board, and if a component becomes damaged or a printed circuit board becomes damaged during this process, then it is possible that the component or entire printed circuit board may have to be discarded. Because the focus of the assembly is on volume and not the value of individual components, a damaged component that must be discarded causes minimal economic loss in the overall assembly process. One technique of monitoring the force of the insertion apparatus on a component involves the use of strain gages on a printed circuit board support table such that excessive force on the component would be translated through the printed circuit board (PCB) to the support table and detected through the attached strain gages. While this is effective, it is fairly complex and a simpler method is needed.
Furthermore, some apparatus may occasionally insert a component improperly, such as in a cocked position, and this misplacement is discovered only after the component has been clinched or soldered to the PCB among a closely spaced field of other electronic components. Consequently, removal of this component may act to damage adjacent components.
Also, during the insertion process different apparatus utilize different techniques to determine whether or not the component leads are properly aligned with their respective holes before insertion. One technique involves the use of complex light detectors that sends light directed from the underside of a through-hole PCB and aligns the component leads based on information supplied by the light detectors. While this method may be effective a simpler and more direct method is needed.
Furthermore, many apparatus are designed to accommodate only one type of electrical component such as an axial component, and provide for other components through the substitution of a gripping device designed solely for the new component configuration.
An object of this invention is to provide an apparatus capable of positioning an electronic component on a through-hole PCB through the use of tactile sensors to limit the insertion force and removing that force if it is determined that a component is not capable of insertion into the PCB.
Another object of this invention is to provide an apparatus capable of sensing incorrect insertion of a component during the insertion process and providing an opportunity for retraction of the component or reinsertion of the component at another location.
Another object of this invention is to provide an apparatus capable of confirming that a component has been properly retrieved from a supply and properly inserted into a PCB.
Still another object of this invention is to provide an apparatus capable of permitting the retrieval and insertion into a through-hole PCB of a variety of differently sized and shaped electronic components, such as axial components, can-type components, or radial components.